Collapsible tap.



F. H. RICHARDS.

COLLAPSIBLE TAP. APPLICATION FILED JUNE 30. 19:0. RENEWED DEC. 15. 1915.

1,188,831. Patented June 27,1916.

3 SHEETS-SHEET I.

I I I I I I I I i Wiinesses:

THE COLUMBIA PLANOGRAPH c0, WASHINGTON, D c.

. FfH. RICHARDS. COLLAF'SIBLE TAP.

APPLICATION FILED JUNE 30, I910- RENEWED DEC- 15, I915- 1,188,831.Patented June 27,1916.

, 3 SHEETS-SHEET-Z- -55- 6 F. H. RICHARDS.

COLLAPSIBLE TAP. APPLICATION man mm: 30.1910. RENEWED use. 15.1915.

3 SHEETS-SHEET 3.

Wiineses: V [220 8222 02 1 %fl@mw M w7 I LUMBIA PMNOCIRAFN'COH WASHNGTON Patented June 27, 1916.

nnrn srars Arena onnron.

, FRANCIS H. RICHARDS, OF HARTFORD, CONNECTICUT.

COLLAPSIBLE TAP.

Application filed June 30, 1910, Serial No. 569,834. RenewedDecember 15,1915.

To all whom it may concern:

Be it known that I, FnANcIs H. Rrormnns, a citizen of the United States,residing in Hartford, in the county of Hartford and State ofConnecticut, have invented certain new and useful Improvements inCollapsible Taps, of which the following is a specification.

The object of this invention is to provide an improved construction ofcollapsible thread-cutting device, such as a tap or a die member, thatwill be strong and reliable in its operation, and can be quicklycollapsed to withdraw it from the threaded article.

In the accompanying drawingsrepresenting one embodiment of my invention,Figure 1 is an end elevation 'with the chasers in the contractedposition. Fi 2 is a side elevation showing the chasers in contracted position. Fig. 3 is an end view similar to Fig. 1 showing the chasers inthe expanded position. Fig. 4 is a section on the line l-4 of Fig. 3showing the chasers in open position. Fig. 5 is a side elevation similarto Fig. 2, with the chasers in the open position. Fig. is a section onthe line 66, indicated in Fig. 4:. Fig. 7 is a section on the line 77indicated in Fig. 4:. Fig. 8 is a rear view as seen on the line 88 inFig. 4, with the rear portion of the body member removed. Fig. 9 showsone of the slides. Fig. 10 shows the spindle for operating the slides;Figs. 11 and 12 show the two chaser members; and Fig. 13 shows the endview of the spindle.

The device is shown as comprising a shell or body member 1 ofsubstantially rectangular form. havingways in it for guiding a pair ofslide members 2 and 3 that are substantially identical; one of which isshown separately in Fig. 9. This way is shown sub stantially in the formof a bore or slot 4:. These slides are shown aseach having anenlargement 5 at their intermediate portion that contains a channel 6extending trans verse to the longitudinal axis of the slide. The bodymember is shown as having an open portion 7 at the intermediate portionof the guideway 4, into which extend thevenlargement 5 of the twoslides, as best shown in Fig. l. The slides are arranged with the twoslots 6 facing each other, and which at certain positions of the slideswill register.

The thread-cutting members, that in the present construction comprisetap segments Specification of Letters Patent.

Patented; June 27, 1916.

Serial No. 66,949.

or chasers, are shown as formed by two members 8 and 9 that aresubstantially identical. Each comprises a cutter or chaser portion 10,and a shank portion 11. Each chamber member has a flat side 12 extendingthroughout the length, which faces are brought together and on whichthey mutually slide in a path transverse to their longitudinal axis, asindicated in Figs. 1 and 3, showing the two different positions of theslides. Fig. 3 shows the chasers in their expanded and operativeposition for engaging a bore to cut a thread therein, and Fig. 1 showsthe chasers in their contracted or closed position, permitting them tobe withdrawn from the tapped bore, out of engagement therewith andwithout requiring re verse rotation of the tap. The shank portions 11 ofthe tap are fitted into the slot portion 6 of the slides, and suitablysecured therein to extend transversely, or perpendicular to the axis ofthe slides. A bolt 13 passes through a bore 14L in each slide, and isscrewed into a threaded hole 15 in each tap; whereby the chasers arerigidly secured to the slides respectively. The body memher 1 isprovided with bores 16 and 17 through which the heads of the bolts 13pass, and which bores are considerably larger than the bolt heads topermit movement of the slides longitudinally in the body. From this itwill be seen that by moving the slides longitudinally or in thedirection of their axis, the two chasers extending transverselytherefrom will be given a movement transverse to the axis of the chaserswhereby they can be shifted to expand and to contract, as described withreference to Figs. 1. and 3. To. insure parallel movement of thechasers, the chaser 8 is provided with a rib 18 fitting into a slot 19in the chaser 9. It will be seen from Figs. a and 5 that the cutterportion of the chaser members projects beyond the body member and cantherefore enter into the bore of any article to cut a thread thereinwithout interference with the body member. v

Me ans are carried by the body member for simultaneously reciprocatingthe slides to effect the contraction and expansion of the chasers. Aspindle 20, shown separately in Fig. 10, is mounted to turn in a bore 21in the body member (see Fig. 4), and is provided with two pins 22 and 23that engage slots 2i and dle and serves to cause the latter to shift theslides. It is the purpose of this lever to engage with any suitablemember of the ma chine in which the device is employed, to shift thechasers at the proper time. Means are also provided for retaining thechasers in the operative or expanded position, and that in the presentdevice comprise an arm 27 connected with the lever 26, which arm engagedby a trip lever 28 pivoted on the body 1, and having a notched extremity29 that will engage the arm 27 and hold the spindle, and with it thechasers, in the operative position. Resilient means are shown tending toshift the lever and spindle to normally retain the chasers in thecontracted or closed position, that will be operative as soon as the arm27 is released from the trip lever 28. A spring plunger is showncomprising a plunger 30 slidable in a bore 31 in the body, and pressedby a coil spring 32 against an abutment 33, formed by a notch in thespindle 20. The trip lever 28 is retained in engaging position by a coilspring 34-; and has an arm 35 which at the proper time can be engaged byany suitable member on the machine to shift the trip lever against theforce of this spring, causing the arm 27 to be released from theabutment of the trip lever. Thereupon the spring plunger described willswing the spindle and cause the V the relative movement of the slides.

chasers to shift to the closed position. It will be understood that whenthe lever 26 is again swung, the arm 27 will slide against the arm 28 ofthe trip lever causing the abutment 29 to engage the arm 27 when thelever 26 is released, and again engage the arm 27 to retain the partswith the chasers in the open or operative position.

Means are provided for adjusting the parts whereby the relative positionof the chasers can be varied, when the arm 27 is engaged by the triplever to hold the parts with the chasers in the open position. Thearrangement shown for this purpose comprises screw bolts 37 and 33carried by the lever 26 and engaging abutment faces 39 and 40 onopposite sides of the axis of the spindle 20, as shown in Figs. 8 and10. These bolts will serve to very nicely adjust the position of thelever 26 upon the spindle, and at the same time to securely lock thelever in the proper position.

If desired, a stop may be arranged on one of the slides carrying thechasers to limit A pin 42 on the slide 2 is-shown as projecting into anopening 43 on the slide 3 and in one direction of movement the pin willengage one wall of this opening l3 and prevent further movement. Therelative movement in the opposite diretcion may be adjustably limited bymeans of a bolt 44 tapped into the slide 3 and projecting into theopening 43 to engage the pin 42.

In Fig. 1 the device is shown with the lever 26 engaged by a suitablestop 45 carried by some part of the machine on which the de vice ismounted, whereby the relative movement between the body member and thisstop will cause the lever 26 to shift to the position indicated in thebroken lines. This is indicated by the stop 45, being also shown inbroken lines as having shifted relatively to the tapping device. But, ofcourse, it will be understood that the stop may be stationary on themachine-and the tap shifted, as for-instance the tap might be mounted ona turret and when advanced from its operative position the lever 26 willengage the stationary stop to shift the lever and thereby set thedevice.

The trip lever 35 will usually be engaged by a suitable stop member, as46, that is movable relative to the tapping device in the stationary oroperative position of the latter and at the end of the cutting operationof the tapthe stop or member 46 is advanced to engage the trip lever 35,causing it to release the arm 27 and permit the chasers to be reset bythe spring plunger.

It will, of course, be obvious that in practice it is indispensable thatthe two chasers S and 9 shall be maintained in accurate po-' sitionlongitudinally in order that the threads thereon shall always conform toa true helical line, after the manner of the corresponding threads inthe ordinary solid taps. The rib or spline 18 carried on. one of saidchasers and fitting into a slot, as 19. in the other chaser constitutesa simple and effective means for preserving this alinement of thethreads. Itwill also be observed that the manner in which the chasersare shifted after the purpose of collapsing them to a smaller thannormal diameter, is by sliding one of these chasers upon and against theother, and this in a direction transverse of the axis of the tap, sothat no open spaces are formed either in opening or closing the tap. Bymeans of this construction the tool is prevented from gathering chipsbetween the working faces of the movable parts thereon so that inpractice it is found the tool can be employed continuously withoutinterference from the accumulation of dirt and chips upon or within thesame.

In practice it is deemed desirable to accomplish. the release of theretaining catch with a minimum, or relatively very slight resistance tothe forward movement of that portion of the machine (such for instanceasthe turret slide of a screw machine) by which the tool is carried.This object I at tain by the long lever arm 38 combined with theactuators 22 and 23 having a relatively short radius of the faces whichengage the tool-carrying slides 8 and 9. lhis arrangement operates toreduce the pressure on the catch faces at 29, to such a small amountthat it becomes feasible to employ a short arm, as 35, on which thetripping stop shall act for fully retracting the latch or catch duringonly a slight advance of the tool, so that the required release iseffected in the briefest possible period of time, thereby to secure aninstantaneous and complete retraction of the cutting teeth, from thework as soon as there is any initial retraction thereof. This importantresult is further accelerated or insured by the direct connection of theactuator and its rigidly-attached lever arm to the two tool-slides,thereby eliminating or avoiding the use of any inter mediate members,and thus preventing the accumulation of play due to wear or otherwise,and so eliminating the injurious results that frequently arise inpractice from such accumulation.

A leading object of my present improvements is to furnish a toolespecially adapted for use in screw-machines where the tools are delugedwith large quantities of heavy oil carrying chips, oxids and dirt, andto prevent these foreign and destructive materials from interrupting theoperation of the tool mechanism through the gradual acclu mulation ofthe same in spaces between the working parts. This result I attain bymeans of a peculiar organization of the working parts wherebychip-spaces are avoided, and whereby no non-contacting opposing andrelatively parallel faces (of a partially exposed spacel have a movementtoward and from each other.

Such features of construction as are herein disclosed but are not hereinclaimed, the same being of my invention, are reserved to constitute inpart the subject-matter of another application to be concurrentlypending herewith; this reservation includes, especially, theconstruction of the cutting parts of the tap-blades as herein set forthin connection with Figs. 11 and 12.

Having thus described my invention, 1 claim:

1. A collapsible thread-cutting device comprising a body member havingways therein, a pair of slides movable in the ways. a chaser carried byeach of the slides and arranged together with their axes transverse tothe slides to expand and contract upon reciprocation of the slides, alever pivoted on the body member, means engaging each slide with thelever to cause reciprocation of the slides in opposite directions onswinging the lever to open and close the chasers, a trip lever carriedby the body and arranged to engage said lever to lock it securing thechasers in open position, and a spring connected with the said formerlever to swing it to cause the chasers to contract when released fromthe trip lever.

A collapsible tl'iread-cutting device comprising a body member havingways therein, a pair of slides movable in the ways, a chaser carried byeach of the slides and arranged together with their axes transverse tothe slides to expand and contract upon reciprocation of the slides, alever pivoted on the body member, means engaging each slide with thelever to cause reciprocation of the slides in opposite directions onswinging the lever to open and close the chasers, a trip lever carriedby the body and arranged to engage said lever to hold it securing thechasers in open position, a spring connected. with the said former leverarranged to swing it to cause the chasers to contract when released fromthe trip lever, the trip lever being arranged to reengage the operatinglever when the latter is returned to shift the chasers to expandedposition.

In a collapsible thread-cutting device, the combination of a body memberhaving a guideway, a pair of contiguous slides mov able in saidguideway, each slide having a channel on its engaging face oppositelylocated and extending transverse to the slide, a pair of similar chaserscomprising a cutting portion and a shank alining therewith, the shankportions of the cutters respectively secured in the said channelportions of the guides with the chasers contiguous substantiallythroughout their length whereby the reciprocation of the slides inopposite directions will cause the chasers to expand and contract theircutting areas, means for simultaneously reciprocating the slides inopposite directions, and means for locking the slides in the expandedposition of the chasers.

4. In a collapsible thread-cutting device, the combination of a bodymember having a guideway. 2 pair of contiguous slides movable in saicguidewz'iy, 3210i] slide having a channel on its engaging faceoppositely located and extending transverse to the slide, a pair ofsimilar chasers comprising a cutting portion and shank aliningtherewith, the shank portions of the cutters respec tively secured inthe id channel portions of the guides with the chasers contiguoussubstantially throughout their length where by the reciprocation of theslides in opposite directions will cause the chasers to expand andcontract their cutting areas, means for simultaneously reciprocating theslides in op 'iosite directions, means for locking the slides in theexpanded position of the chasers, one chaser having a transverse slot.and a rib on the other chasers fit ing said slot to guide the chasers.

5. In a collapsible thread-cutting device. the combination of a bodymember, a pair of contiguous slides movable in said guide way, eachslidehaving a channel on its engaging face oppositely located andextending transverse to the slide, a pair of similar chasers comprisinga cutting portion and a shank alining therewith, the shank portions ofthe cutters respectively secured in the said channel portions of theguides with the chasers contiguous substantially throughout their lengthwhereby the reciprocation of the slides in opposite directions willcause the chasers to expand and contract their cutting areas, means forsimultaneously reciprocating the slides in opposite directions, meansfor locking the slides in the expanded position of the chascrs, andguiding means between the chasers.

6. In a collapsible thread-cutting device, the combination of a bodymember, a pair of contiguous slides movable in said guide way, eachslide having a channel on its engaging face oppositely located andextending transverse to the slide, a pair of similar chasers comprisinga cutting portion and a shank alining therewith, the shank portions ofthe cutters respectively secured in the said channel portions of theguides with the chasers contiguous substantially througlr out theirlength whereby the reciprocation of the slides in opposite directionswill cause the chasers to expand and contract their cutting are; s,means for simultaneously reciprocating the slides in oppositedirections, means for locking the slides in the expanded position of thechascrs, and a spring device carried by the body member for normallyretaining the chasers in their contracted position.

7. In a collapsible thread-cutting device, the combination of a bodymember having a guideway, a pair of contiguous slides movable in saidguideway, a pair of similar chasers secured in the said slides whereby,

the reciprocation of the slides in opposite directions will cause thechasers to expand and contract their cutting areas, a slide actuatingspindle for simultaneously reciprocating the slides in oppositedirections, a spindle carried by the body to swing, a pair of pinsprojecting from the spindle. the slides each having a notch engaged byone of the pins, a lever carried by the spindle, and means for adjustingthe lever on the spindle, whereby to adjust the working of said slidesand chasers. V

S. In a collapsible thread-cutting device, the combination of a bodymember having a guideway.v a pair of contiguous slides movable in saidgi'iideway, a pair of similar chasers secured in the said channelportions of the slides with the chascrs contiguous whereby thereciprocation of the slides in opposite directions will. cause thechasers t expand and contract their cutting areas, means forsimultaneously reciprocating the slides in opposite directions,comprised of a spindle carried by the body to swing and having anabutment portion, a pair of pins projecting from the spindle, the slideseach having a notch engaged by one of the pins, an actuating levercarried by the spindle to cause the said reciprocation of the slides,and a spring plunger in the body engaging said abutment to normallycause the spindle to retain the chasers in closed position.

9. In a collapsible thread-cutting device, the combination of a -bodymember having a guideway, a pair of contiguous slides movable in saidguideway, each slide having a channel on its engaging face oppositelylocated and extending transverse to the slide, a pair of similar chaserscomprising a cutting portion and a shank alining therewith, the shankportions of the cutters respectively secured in the said channelpertions of the guides with the chasers contiguous substantiallythroughout their length whereby the reciproci'ition of the slides inopposite directions will cause the chasers to expand and contract theircutting areas and means for simultaneously reciprocating the slides inopposite directions, comprised oi a spindle carried by the body toswing, a pair of pins projecting from the spindle, the slides eachhaving a notch engaged by one of the pins, an actuating lever carried.by the spindle to cause the said' reciprocation of the slides. V

10. In a collapsible thread-cutting device, the combination of a bodymember having a guidcway, a pair of contiguous slides;mov able in saidguideway, a pair of similar chascrs secured in the slides whereby thereciprocation of the slides in opposite directions will cause thechascrs to expand and contract their cutting'areas, means forsimultaneously reciprocating the slides in opposite directions,comprised of a spindle carried by the body to swing, a pair of pinsprojecting from the spindle, the slides each having a notch engaged byone of the pins, an actuating lever carried. by the spindle to cause thesaid reciprocation of the slides, a latch ",ar pivoted on the body andhaving an abutment arranged to engage the lever to lock it in positionto retain the chasers in the expanded position, 'a spring member in thebody arranged to engage the spindle to swing it to shift the chasers tocontracted position whenthe lever is released from the trip member, anda spring engaging the trip member causing it to engage said lever whenthe latter is swung to shift the chasers to expanded posi tion. 7

11. In a collapsible thread-cutting device, the combination of a bodymember having a guideway, a pair of contiguous slides movable in saidguideway, each slide having a channel. on its engaging face oppositelylocated and extending transversely to the opposite directions will causethe chasers to expand and contract their cutting areas, means forsimultaneously reciprocating the slides in opposite directions, aspindle carried by the body to swing, a pair of pins projecting from thespindle, the slides each having a notch engaged by one of the pins, alever carried by the spindle to cause the latter to reciprocate theslides in opposite directions a latch bar pivoted on the body and havingan abutment arranged to engage the lever to lock it in position toretain the chasers in the expanded position, a spring member in the bodyarranged to engage the spindle to swing it to shift the chasers tocontracted position when the lever is released from the trip member, anda spring engaging the trip member causing it to engage said lever whenthe latter is swung to shift the chasers to expanded position.

12". A collapsible thread cutting device comprising a body member havingways therein, a pair of chaser-carrying members slidable in the ways toexpand and contract the cutting portions of the chasers and having theircontacting faces in a plane through the axis of the bodyanember, anactuator engaging directly with both of said members to simultaneouslyopen and close the chasers, an operating member connected with theactuator by means that are adjustable and arranged for varying theposition of the chasers for a given movement of the operating member bysliding the chasers on each other face to face, substantially asdescribed.

13. A collapsible thread cutting device comprising a body member havingways therein, a pair of chaser carrying members slidable in the ways toexpand and contract chasers, an actuator engaging said members tosimultaneously open and close the ch asers, an operating memberconnected with the actuator by means that are adjustable to vary theposition of the chasers for a given movement of the operating member,actuator adjusting devices and a spring plunger carried by the bodymember engaging the operating member to shift it to one limit of itsmovement and which is independent of the said adjustment means.

14. A collapsible thread cutting device comprising a body member havingways therein, a pair of chaser members slidable in the ways to expendand contract their cutting portions, an actuator engaging said membersto simultaneously open and close the chasers, an operating member, andconnections between the actuator and the said member comprising twoabutment faces on one member and adjusting screws on the other memberarranged to engage said faces to vary the position of the operatingmember relative to the actuator.

15. A collapsible thread cutting device comprising a body member havingways therein, a pair of chaser members slidable in the ways, a spindlemounted to turn in the body, connections between the spindle and chasermembers to cause them to open and close when swung, a lever connectedwith the spindle to swing it, a trip lever having a fixed abutmentengaged by said lever to hold the chasers in their cutting position, thesaid connection of the spindle and the lever being adjustable to varythe position of the chasers when the lever is engaged by the saidabutment to hold the chasers in cutting position.

16. A collapsible thread cutting device comprising a body member havingways therein, a pair of chaser members slidable in the ways, a spindlemounted to turn in the body, connections between the spindle and chasermembers to cause them to open and close when swung, a lever connectedwith the spindle to swing it, a trip lever having an abutment engaged bysaid lever to hold the chasers in their cutting position, the saidconnection of the spindle and the lever being adjustable to vary theposition of the chasers when the lever is engaged by the said abutmentto hold the chasers in cuttingposition, said connection comprisingabutment faces on the spindle on opposite sides of its axis, andadjusting screws on the lever engaging said abutments respectively.

17. In a collapsible thread cutting device, the combination of a bodyhaving a guideway, a pair of chaser members slidable in the guideway toopen and close, actuating means including a lever forshifting thechasers, a trip lever having an abutment engaged by said lever to holdthe chasers in cutting position, a spring connected with the operatinglever arranged to hold it against said abutment of the trip lever and toswing the lever when the trip lever is shifted, and an adjustable stopmember arranged to engage the operating lever when swung to re-engagethe abutment face of the trip lever in order to prevent the lever movingtoo far when swung to engage the trip lever abutment face.

18. A collapsible thread cutting device comprising a body member havingways therein, a pair of elongated slides longitudinally movable insaidways with their opposed faces in engagement, each slide having atransverse channel in the engaging face at the intermediate portion, apair of chasers comprising a cutter portion and a shank portion aliningtherewith, the shank portion of each chaser being secured in the saidchannel portion of the slides respectively causing the chasers to extendtrans-.

versely to the slides, the chasers having opposed faces in engagementsubstantially throughout their length and located in the plane of theengaging faces of the slides, and means for shifting the slides endwiseto cause the chasers to shift transversely to their axis to open andclose their cutter portions.

19. A collapsible thread cutting device comprising a body member havingways therein, a pair of slides longitudinally movable in the ways withtheir opposing faces in engagement substantially their whole length, apair of chasers each comprising a cutter portion and a shank portion,each. chaser being secured to one of said slldes,

. length, a pair of chasers each comprising a cutter portion and a shankportion, each chaser being secured to one of said slides, the chasershaving engaging faces extending substantially throughout their lengthand parallel with the engaging faces of the respective slides, and meansfor shifting the slides endwise to cause relative movement of thechasers transverse to their axis, one of the chasers having a slot inits engaging face at the shank portion, the other chaser having a ribprojecting from its shank portion into said slot in the other chaser toguide the chasers.

21. In a collapsible threading tool, the combination with a tap-bladecarrier com prising two tap-blade'carrying members shiftable onerelatively to the other laterally of the axis of the tool, and a singlepair of tap-blades projecting forwardly of the carrier, one blade oneach carrier respectively, and each blade having on the forwardlyprojecting part thereof threadcutting teeth and having on the oppositeedge thereof a curved face shiftable outwardly from the axis forguarding the teeth of the opposite blade when the tap is collapsed forwithdrawal from a threaded hole, said blades and the carriers thereforbeing arranged in face to face contact in one plane which is an axialplane of the tool.

22. In a collapsible threading tool, the

combination with a tap-blades carrier comprising two tap-bladecarrier-slides shiftable one relatively to the other laterally of theaxis of the tool, and two tap-blades projecting forwardly of the carrierone blade on each carrier-slide respectively, and each blade having onthe forwardly projecting part thereof thread-cutting teeth and having onthe opposite edge thereof a curved face shiftable outwardly from theaxis for guarding the teeth of the opposite blade when the tap iscollapsed for withdrawal from a threaded hole, said blades and thecarriers therefor being arranged in face to face contact in an axialplane of the tool.

23. In an adjustable collapsing tap, in combination, a pair of tap-bladecarriers having each a tap-blade seat, and located and movable face toface in contact in an axial plane of the tap, and arranged for holding apair of tap-blades in axial alinement and disposed longitudinallythereof; a pair of tap-blades arranged face to face and longitudinallyof said axis, fastening means arranged for removably securing the bladesin said carrier blade-seats, and arranged for the blades to be withdrawnfrom said seats longitudinally of the axis, and operating andstroke-adjusting means for said carriers arranged for shifting onecarrier relatively to the other transversely of said axis, whereby thecentrally-located tapblades and the carriers meet and move with theircontacting faces in'one and the same central working plane.

24. In an adjustable collapsing tap, in combination, a pair of tap-bladecarriers having each a tap-blade seat, and located and movable face toface in contact in an axial plane of the tap, and arranged for holding apair of tap-blades in axial alinement and disposed longitudinallythereof; a pair of tap-blades arranged face to face and longitudinallyof said axis, fastening means arranged for removably securingthe bladesin said carrier blade-seats, and arranged for the blades to be withdrawnfrom said seats longitudinally of the axis, operating andstrokeadjusting means for said carriers arranged for shifting onecarrier relatively to the other transversely of said axis, andpitch-alining guide-faces between the blades and arranged in positionfor preventing longitudinal movement of one blade relatively to theother while permitting the transverse movement of the blades with theirrespective carriers,

25. In an adjustable collapsing tap, in

combination, a pair of tap-blade carriers having each a tap-blade seat,and located and movable face to face in contact in an axial plane of thetap, and arranged for holding a pair of tap-blades in axial alinementand disposed longitudinally thereof;

a pair of tap-blades arranged face to face 1 and longitudinally of saidaxis, fastening means arranged for removably securing the blades in saidcarrier blade-seats, and arranged for the blades to be Withdrawn fromsaid seats longitudinally of the axis, operating and stroke-adjustingmeans for said carriers arranged for shifting one carrier relatively tothe other transversely of said. axis and pitch-alining means operativebetween the blades for preventing l0ngitudinal movement of one bladerelatively to the other While permitting the transverse movement of theblades relatively to each other.

FRANCIS H. RICHARDS.

lVitnesses FRED. J. DOLE, GUSTAV Dnnws.

flopies e! this patent may be obtained for five cents each, byaddressing the Commissioner of Patents Washington, I). C."

